We are requesting an in vivo multiphoton microscope for the UT Southwestern Live Cell Imaging Facility (LCIF), a campus wide core facility that provides access to optical microscopy instrumentation for more than 150 researchers from 35 departments on the campus of UT Southwestern Medical Center in Dallas. This instrument will provide access to technology that currently is unavailable to researchers on the UT Southwestern campus. To accommodate imaging in live animals, explanted organs and tissue slices, we are requesting a Zeiss LSM 710 mounted on an AxioExaminer upright microscope with two Coherent Vision II Ti:Sapphire lasers. The system is configured to permit simultaneous two photon imaging and two photon photoactivation, imaging of forward directed SHG, and simultaneous imaging of backward directed SHG with two fluorescence channels. We are requesting a GaAsP detector for detecting very weak signals such as occur when imaging deep into tissue in live animals or imaging fluorescence signals where expression levels are near endogenous levels, such as in transgenic animals where the transgene is under the control of the endogenous promoter. The health-related research projects that will be enabled by the addition of this technology include studies of brain function, immune responses, wound healing, heart disease, and premature birth.